Oscillographic transient recorder



June 6, 1933. c. M, HATHAWAY 1,913,200

QSCILLOGRAPHIC TRANSIENT RECORDER 2 Sheets-Sheet 1 Filed Oct. 7, 1931 W w ra m O n 0 tt t h A 1m 5 6 H d u a. C

June 6, 1933. c. M. HATHAWAY 1,913,200

OSCILLOGRAPHIC TRANSIENT RECORDER Filed Oct. 7, 1931 2 Sheets-Sheet 2 Fig.2.

Inventor-z Claude M. Hath away.

byM eu H i5 Abbey" may.

Patented June 6, 1933 UNITED STATES PATENT OFFICE CLAUDE I. HA'IHA'WAY, OI MIDI-ADO SPRINGS, MIDI-ADO, 816x03 '10 GENERAL ELECTRIC column, A. CORPORATION 01' NEW YORK OBGILLOGWHIO RECORDER Application ma 0mm 7, 1081. mm 10. sauna This invention relates to oscillographs and more particularly to a method and means pertaining to such an oscillograph whereby its recording is started very shortly after the occurrence of a disturbance caused by a transient. I

An oscillograph which is used for recording transients should be set into operation by the transient since the cost of continuous operation would be very great due to the very large use of film. At the same time the recording on the film must occur very shortly after the transient comes into existence in order to record a major part of such transient. In my invention I propose to accomplish these desirable results y having the transient set a body of small inertia into motion for the initial recording during which time a film moving motor comes u to full speed and causes the recording 0 the remainder of the phenomenon on the film in the usual manner.

A better understanding of the invention can be had and further objects of the invention will appear from the following specification taken in connection with the accompanying drawings in which Figure 1 is a schematic representation of my invention and Figure 2 shows various modifications whereby the operation becomes entirely automatic.

The initial recording in my invention is caused by the movement of a mirror which reflects a beam of light along the length of the film. The method of doing this can be better understood by referring to Fi 1 in which 10 is a lamp which reflects its light to the galvanometer mirror 11 by means of the spherical lens 12, the prism 13 and the slit aperture control 14. This latter member is provided with a lever arm 16 and aperture 15 which allows the amount of light reaching the galvanometer mirror 11 to be controlled. This galvanometer mirror oscillates responsive to the characteristics of the current in the line 17 to which it is connected by means of current transformer 18. The light reflected from galvanometer mirror 11 is reflected through the cylindrical lens 11 and is prevented from reaching the rotatable mirror 18 during normal conditions of the line by the shutter vane 19. The shutter vane 19 and mirror 18 are rigidly fastened to the shaft 20 which in turn is rigidly fastened to armature 21 which latter member is of magnetic material or provided with a magnetic part 21. In its non-operating position this armature 21 is held at one end to a permanent magnet 22 against the force of a spring 23, fastened to its opposite end. Between pivot 24 and the end of the lever influencedby the magnet 22, the armature of relay 4:7 is attached. The armature, when the rela is sufliciently energized through the line 1 to which it is connected by means of current transformer 25, will cause the armature 21 to rotate about its axis against the force of magnet 22. The ma net 22 may be of special shape as shown in ig. 2 in which the magnetic reluctance between the poles is very small so that the lines of force of the magnet will not influence the lever arm after it has moved a short distance from the magnet. The first few degrees of rotation of armature 21 take place very rapidly due to the lost motion device 26. During these first few degrees of motion of armature 21 the shutter vane 19 is rotated sufficiently so that at the point where the lost motion of lost motion device 26 is taken up the shutter vane has been rotated sufiiciently so that the light from galvanometer mirror can reflect on mirror 18. At the same time that light reaches this mirror, the sliding contacts 27 and 28 engage and place motor 29 across battery 30. After the lost motion of device 26 is taken up, the armature 21 will continue to rotate but at a rate of speed depending on the setting of dashpot 31. The mass of small inertia, i. e. the mirror 18, being rigidly fastened to armature 21, also rotates at a uniform rate of speed and traces a record of the condition of circuit 17 on the film 34 between points 32 and 33. During the rotation of this mirror and after the contacts 27 and 28 have engaged, the motor 29 will be coming up to speed so that by the time the motion of the armature 21 and consequently the motion of mirror 18, has ceased due to the plunger of the dashpot 31 having reachedthe bottom of the dashpot, the motor will be operating at full speed and will be moving the film 34, a mass of relatively large inertia as compared to the mirror, from right to left at a uniform rate of speed. The movement of motor is imparted to the film by means of meshed gears 35 and 36, pulleys 37 and 38, and pulley belt 39. It can readily be seen that it will require much less time to set the mass of small inertia consisting of a mirror into condition for recording than it would be to set the mass of large inertia consisting of the film into such condition. The move ment of the motor is imparted to the film by means of meshed gears 35 and 36, pulleys 37 and 38, and pulley belt 39.

For resetting mirror 18 I have rotatably mounted on shaft 20 lever arm41 with a projecting arm 42, fastened in operative relation to armature 21. Lever arm 41 is pivoted to the armature of relay 43. By closing push button 40, the relay 43 is connected in series with battery 30, causing the armature to move downward which in turn moves lever arm 41. The movement of armature 41 allows projecting arm 42 to strike armature 21, thus resetting this armature to its original position, where it will be held by magnet 22, it being asssumed that the high current transient condition has passed.

In the modification shown in Fig. 2 in which the motor 29, battery 30, lamp 10 and relay 47 are the same as in Fig. 1, the recording of the transient and the resetting of the apparatus takes place automatically. Although not shown the optical system including galvanometer mirror 11 actuated by current transformer 18, the film, film rolls and driving connections between these rolls and the motor will be as illustrated in Fig. 1. The shaft 20 supporting the mirror 18 and shutter vane 19 will be connected to armature 21 of relay 47 at point 24 in Fig. 2. The connections and operation of this modification will now be described in detail.

The current transformer 25 is connected to the circuit 17 and to the starting relay 61 which relay has an adjustable tripping value by means of taps taken to switch 45. The armature 46 is controlled by starting relay 61 and in its lower position this armature closes the circuit from the energizing winding of mirror rotating relay 47 through the battery 30. In its upper position the armature 46 closes the circuit between battery 30 and relay 48 which relay when excited causes its armature 49 to short-circuit starting relay 61. During normal conditions of the line 17 the relay 47 attracts its armature 21 so that contacts 50 and 51 are separated. When starting relay 61 is tripped, the circuit through coil of re ay 47 is opened causing this relay to become deenergized which allows spring 23 to rotate armature 21 about its pivot point 24 in a clockwise direction.

The first few degrees of this movement will be rapid because of the lost motion device 26 but subsequent speed of movement is controlled through the dashpot 31. The first few degrees of motion of armature 21 closes contacts 50 and 51 completing the circuit of relay 58 which operates and closes contacts 59 between motor 29 and battery 30, and short-circuits resistance 52 so that lamp 10 which is in the circuit with battery 30 will burn more brightly.

The motor 29 which drives the film also controls the operation of cam 53, rotating it in a clockwise direction through a train of gears. Cam 53 is provided with projecting arms 54 which control the operation of lever arms 55 and 60. Lever 60 operates contacts 56 which are in circuit with relay 57. Lever arm 55 operates contacts 62 which are in circuit with miror resetting relay 43.

The operation of the above described modification will be obvious to those skilled in the art but for the purpose of rendering the description complete, I shall describe the operation as follows:

An impulse in line 17 causes the armature 46 of starting relay 61 to break its lower contacts and close its upper ones. The breaking of the lower contacts takes place very quickly because of the shape of permanent magnet 22. the operation of which has been described above. The separating of these contacts opens the circuit between battery 30 and the coil of relay 47 allowing armature 21 to be turned clockwise by spring 23. The first few degrees of movement of this armature are free due to lost motion device 26. At the point that this lost motion ceases the plunger of dashpot 31 becomes damped due to the damping means contained therein, and the contacts 50 and 51 become closed which energizes the winding of relay 58 closing contacts 59. The closing of these contacts places motor 29 across the battery 30 and short-circults resistance 52, causing the lamp 10 to give a brighter light. As lever 21 rotates it causes the mirror 18 which is rigidly fastened to it at point 24, to swing the beam of light from point 32 to point 33 (see Fig. 1). The constants of the system are so selected as to allow motor 29 to have reached its full speed at the same time that lever arm 21 has reached the end of its motion, thus insuring a continuous record of the phenomenon on line 17 since the film is now moving at its normal speed from right to left as shown by the arrow in Fig. 1.

As the cam 53 rotates with the motor, one of its projecting arms strikes lever arm 60 momentarily closing contacts 56 and resetting starting relay 61. In its travel this camprojecting arm then strikes lever arm 55 and momentarily closes contact 62 which resets armature 21. The resetting of armature 21 .1565 the contacts 50 and 51 to be opened,

thus deencrgizing coil 58 and stopping motor 29. If the abnormal conditions on the line 17 still exist when relay 57 is energized, the armature 22 will be immediately attracted to its upper position, causing relay 48 to be energized, the armature of which keeps the circuit throu h relay 43 open and preventing this relay rom resetting the mirror 18. Since most transients are of very short duration, the resetting of mirror 18 can be accomlished very quickly by increasing the numer of projecting arms 54 or by increasing the speed of cam 53 by changing the gear ratio of the gears between the cam and the motor. It should be noted that after relay 61 attracts armature 46, its winding is immediately short circuited by relay 48, thus insuring that relay 57 can reset armature 46 when contacts 56 are closed. If a transient is still on line 17, the armature 46 will be tripped before relay 43 can reset mirror 17.

While I have described particular embodiments of my invention, and certain apparatus for carrying out my method, it will be obvious to those skilled in the art that various modifications may be made without departing from the spirit of my invention and I therefore desire to cover all such modifications as fall Within the scope of my invention in the ap ended claims.

What claim as new and desire to secure by Letters Patent of the United States, is:

1. A method of operating a record tracing means to trace a record of a transient, which record tracing means includes a member of relatively large inertia requiring an interval of time to reach the proper speed for tracing the record, and a member of small inertia which can be started into movement quickly, which comprises moving the member of small inertia temporarily during the initlal portion of the transient to trace a record of such portion and bringing said member of relatively large inertia to the proper speed during such temporary motion of said member of small inertia.

2. Apparatus for tracing a continuous rec- 0rd including a movable record means having relatively large inertia and a member movable with respect to said record means and having relatively small inertia, means responsive to the condition to be traced for bringing said record means up to proper speed, and means for moving sald small inertia member during the interval required for said record means to reach the proper speed.

3. In a graphic recording device responsive to variations in magnitude of a quantity to be recorded, means for producing a beam of light, means for moving a record film, means for deflecting said light beam across the film transverselyto the direction of movement of the film in accordance with variations in the quantity to be recorded,

means for initiating the operation of said recording device, and means actuated in response to the operation of said initiating means for causing said beam of light to be deflected along said record film counter to the normal direction of motion of said film to provide a record of the variations in the quantity to be recorded occurring before the movable film has been brought up to speed.

4. In combination with an electrical'circuit, a graphic transient recorder comprising a lig t beam, light beam deflecting means res onsive to variations in circuit conditions an means for moving a hotographic film, means for setting said fi m moving means into motion, a quick-acting relay connected in said electrical circuit serving to start said recorder in operation upon the occurrence of a transient, and auxiliary means for causing the li ht beam to travel along said photographic 1m to record the initial stages of said transient occurring before said film has come up to speed.

5. In combination with an electric circuit, an oscillograph comprising a galvanometer mirror which oscillates responsive to normal and abnormal conditions of the circuit, film holding means, a second mirror adapted to receive only the oscillations of said galvanometer mirror which are caused by abnormal conditions of said circuit, relay means responsive to abnormal conditions of said circuit for causing the rotation of said mirror along a part of the time axis of the record produced by the abnormal circuit conditions, a motor for moving said film holding means and a relay for controlling said motor in response to the operation of said mirror rotating relay means and which relay causes said motor to reach its full speed, when said mirror has reached the end of its rotation.

6. In an oscillograph means responsive to abnormal phenomena, a mirror rotatable through a part of one revolution, means responsive to said abnormal phenomena responsive means for rotating said mirror, a motor, means responsive to theoperation of said mirror rotating means for controlling said motor, cam means operated by said motor, means responsive to the operation of said cam for resetting said abnormal phenomena responsive means, means responsive to the operation of said cam for resetting said mirror rotating means and means responsive to said abnormal phenomena-responsive means for preventing said mirror rotating means from resetting during the existence of the abnormal phenomena.

7. Anoscillograph comprising a film means, a light source, a galvanometer mirror located between the film and light source which mirror oscillates res onsive to both normal andabnormal circuit phenomena, a second mirror rotatable through a part of one revolution adapted to receive the light impulses reflected from said galvanometer mirror when said alvanometer is oscillating responsive to a normal phenomena and to trace a record of said phenomena on the film through the path of its rotatlon, and means for moving said film so as to trace said phenomena on said film after the second mentioned mirror has reached the end of its rotation.

8. An oscillograph comprising a film means, a light source, a galvanometer mirror interposed between the film and light source which mirror oscillates responsive to both normal and abnormal circuit phenomena, the latter of which is to be recorded, a mirror rotatable through a part of one revolution, and adapted to receive the light impulses A reflected from said galvanometer mirror when said galvanometer mirror is oscillating responsive to abnormal phenomena and to trace a record of said phenomena on the film through the path of the rotation of said second mirror, means for moving the film to obtain a trace of the record of the remainder of said abnormal phenomena after said mirror has reached the end of its rotation and means responsive to normal phenomena and operated by said film-moving means for resetting said rotatable mirror.

9. An oscillograph comprising a film means, a light source, a galvanometer mirror interposed between the film and light source, which mirror oscillates responsive to normal and abnormal circuit phenomena, the latter of which is to be recorded, a rotatable mirror adapted to receive the light impulses reflected from said galvanometer mirror when said mirror is oscillating responsive to abnormal phenomena, and to trace the first portion of the record of said phenomena on the film, means for moving the film for tracing a record of the remainder of said phenomena, means operated by said film-moving means for resetting said rotatable mirror and means operated by the film-moving means and responsive to abnormal phenomena for preventing said rotatable mirror from resetting during the existence of abnormal phenomena.

10. In combination with an electric circuit, a graphic transient recorder comprising a light beam, light beam deflecting means responsive to variations in circuit conditions and a movable film means cooperating therewith, means for setting said film means in motion, a relay serving to start said recorder operation connected so as to be responsive to the occurrence of a transient in said circuit, said relay including a coil, an armature attracted to said coil during the existence of a transient in said circuit, and a permanent magnet opposing the attraction of said coil and having a yoke construction with the ends of its yoke inclose proximity to each other whereby the movement of said hand.

CLAUDE M. HATHAWAY. 

